Collection and synchronisation.

[wesley]

Hi List,

I have a question on collection synchronisation. For example I have an
ArrayList called myList and the code is like this:

lock (myList.SyncRoot)
{
// do update on myList
Monitor.PulseAll(myList.SyncRoot);
}

Question, do I need to do Monitor.PulseAll() in here? Because the code above
is potentially accessed by several thread.

Thanks,

Wes

[William Stacey [MVP]]

Not sure what your doing, but you don't need pulse here. All other threads
will block on lock (if they lock the same syncRoot instance) and be release
in turn as lock is released. hth

--
William Stacey, MVP

"wesley" <we*@inthemix.com.au> wrote in message
news:uh**************@TK2MSFTNGP10.phx.gbl...

Hi List,

I have a question on collection synchronisation. For example I have an
ArrayList called myList and the code is like this:

lock (myList.SyncRoot)
{
// do update on myList
Monitor.PulseAll(myList.SyncRoot);
}

Question, do I need to do Monitor.PulseAll() in here? Because the code above is potentially accessed by several thread.

Thanks,

Wes

[wesley]

Thanks,

I got confused a bit with the Monitor.Pulse/PulseAll doc because it says
here:
"The thread that currently owns the lock on the specified object invokes
this method to signal all threads waiting to acquire the lock on the object.
After the signal is sent, the waiting threads are moved to the ready queue.
When the thread that invoked PulseAll releases the lock, the next thread in
the ready queue acquires the lock."

So I thought I need to do Pulse so the other thread waiting can try to get
the lock.

Thanks,

wes

Not sure what your doing, but you don't need pulse here. All other threads will block on lock (if they lock the same syncRoot instance) and be release in turn as lock is released. hth

--
William Stacey, MVP

Hi List,

I have a question on collection synchronisation. For example I have an
ArrayList called myList and the code is like this:

lock (myList.SyncRoot)
{
// do update on myList
Monitor.PulseAll(myList.SyncRoot);
}

Question, do I need to do Monitor.PulseAll() in here? Because the code

above

is potentially accessed by several thread.

Thanks,

Wes

[William Stacey [MVP]]

That is when your doing fancier stuff with monitor and waits, etc (i.e.
readers and writers). Normally you can just use "lock()" for many things.
lock actualy is sugar for Monitor.

--
William Stacey, MVP

"wesley" <we*@inthemix.com.au> wrote in message
news:Of**************@TK2MSFTNGP11.phx.gbl...

Thanks,

I got confused a bit with the Monitor.Pulse/PulseAll doc because it says
here:
"The thread that currently owns the lock on the specified object invokes
this method to signal all threads waiting to acquire the lock on the object. After the signal is sent, the waiting threads are moved to the ready queue. When the thread that invoked PulseAll releases the lock, the next thread in the ready queue acquires the lock."

So I thought I need to do Pulse so the other thread waiting can try to get
the lock.

Thanks,

wes

Not sure what your doing, but you don't need pulse here. All other

threads

will block on lock (if they lock the same syncRoot instance) and be

release

in turn as lock is released. hth

--
William Stacey, MVP

Hi List,

I have a question on collection synchronisation. For example I have an
ArrayList called myList and the code is like this:

lock (myList.SyncRoot)
{
// do update on myList
Monitor.PulseAll(myList.SyncRoot);
}

Question, do I need to do Monitor.PulseAll() in here? Because the code

above

is potentially accessed by several thread.

Thanks,

Wes